LTE CDRX Inactivity Timer Adjustment for Hybrid Tune Away
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Solution Overview
Problem
In LTE connected discontinuous reception (CDRX) mode, single-radio hybrid tune away devices face data throughput loss due to missed PDCCH grants when tuning away from the LTE network, as the inactivity timer expires during the tune away gap, preventing the device from entering the CDRX OFF state and resulting in continued monitoring and power consumption.
Innovation Solution
The inactivity timer is reset upon returning to the LTE network, allowing the device to remain awake and monitor for PDCCH grants until the timer expires, ensuring no data throughput loss and improving LTE performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the device tunes away from LTE network to monitor second RAT network signals, then multi-network compatibility is improved, but PDCCH grants are missed causing data throughput loss
Solution Approach 1:
The device determines whether the inactivity timer will expire during the tune away gap before actually tuning away. Based on this preliminary assessment, it proactively adjusts the timer value or extends the CDRX ON duration to prevent expiration during the gap, ensuring no PDCCH grants are missed while still allowing tune away functionality
2Use of energy by moving object
If the inactivity timer expires during tune away gap, then power consumption is reduced by entering CDRX OFF state, but PDCCH grants are missed
Solution Approach 1:
The device continuously monitors downlink data activity and uses this feedback to dynamically adjust the inactivity timer value. When activity is detected, the timer is reset or extended, ensuring the device remains awake to receive PDCCH grants. This feedback mechanism balances power consumption with reliable grant reception
3Reliability
If the device remains awake to monitor PDCCH continuously, then no PDCCH grants are missed, but power consumption increases
Solution Approach 1:
The device dynamically adjusts its monitoring behavior based on downlink data activity. The inactivity timer value is made dynamic rather than fixed, allowing the device to transition between active monitoring and power-saving states adaptively. This dynamic approach ensures reliable PDCCH reception when needed while reducing power consumption during idle periods
4Reliability
If the inactivity timer value is extended to prevent expiration during tune away, then PDCCH grant reception is improved, but CDRX cycle efficiency decreases
Solution Approach 1:
The device changes the inactivity timer parameter based on detected downlink data activity and tune away scheduling. Rather than using a fixed extended timer value, the system adapts the timer parameter dynamically, extending it only when necessary to cover the tune away gap, thereby maintaining CDRX cycle efficiency while ensuring reliable PDCCH reception
Data Source
AI summary
Certain aspects of the present disclosure relate to techniques and apparatus for optimizing long term evolution (LTE) connected discontinuous reception (CDRX) for single radio hybrid tune away devices. Certain aspects provide a method for wireless communications by a user equipment (UE). The method generally includes entering a DRX mode wherein the UE alternates between an activity period and an inactivity period while connected to a first radio access technology (RAT) network, tuning away from the first RAT network for a tune away period to monitor signals in a second RAT network, determining when an inactivity timer for the DRX mode expires or will expire, and adjusting a value of the inactivity timer based, at least in part, on the determination.